This paper describes the amplifier and beam shaping section of a new pulse generation system that will drive the Beamlet laser at LLNL. The master oscillator and pulse shaping system are described in an accompanying contribution [R. B. Wilcox ea., `Fusion Laser oscillator and pulse-forming system using integrated optics.', these proceedings]. A modified regenerative amplifier produces a gain of 109 to bring the oscillator pulses to the mJ- level. A serrated aperture and birefringent beam shaper produce a flat-topped square beam with high fill factor. A single four-passed Nd:glass rod amplifier provides sufficient gain to generate the desired 12 J output energy in a 3 nsec pulse with very small beam profile, wavefront and pulse shape distortion. We present a description of the system components, followed by a discussion of its performance, based upon over 150 full front end shots being completed since its assembly.